The invention relates to novel liquid crystalline ferroelectric derivatives of branched acyclic alpha-chlorocarboxylic acids.
Liquid crystalline ferroelectric compounds are described in the literature. They are optically active compounds, which are predominantly derivatives of the optically active amyl alcohols and optically active alpha-chloropropanols (P. Keller, S. Juge, L. Liebert, L. Strzelecki: C.R. Acad. Sci., Ser. 282 C, 639 (1976); P. Keller: Ann. Phys. 139-44 (1978); M. V. Loseva, B. I. Ostrowskii, A. Z. Rabinovich, A. S. Sonin, B. A. Strukov, N. I. Chernova: Pis'ma Zh. Eksp. Teor. Fiz. 28, 404 (1978); A. Hallsby, M. Nilsson, B. Otterholm: Mol. Cryst. Liq. Cryst. 82, 61-8 (1982); P. Keller: Ferroelectrics 1984; J. W. Goodby, T. M. Leslie: Mol. Cryst. Liq. Cryst. 110, 175 (1984). However, when used in displays with memory properties, these substances have a series of disadvantages, such as very high melting temperatures, instability towards heat, light or chemical influences or very low dipole moments, which bring about low values for the spontaneous polarization.
It is an object of the invention to find substances, which exhibit good stability towards heat, light and chemical influences, have low melting points and show sufficiently high dipole moments.